CHICAGO (CBS) — Chicago Police have issued a warning about a string of armed robberies this month on the city’s South Side.

Some robbers had high-powered weapons, terrorizing store owners.

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CBS 2’s Brandon Merano talked to people at two businesses that were hit this month in the Deering (9th) District, which includes Brighton Park, McKinley Park, Bridgeport, Back of the Yards, Fuller Park, Armour Square, and parts of Gage Park.

The business owners are shaken up. One business owner with whom Merano spoke even went as far as hiring security at his shop.

A call went out to police for a robbery in progress at Mario’s Cigar & Vape Shop, at 224 W. 31st St. in the Armour Square neighborhood earlier this month.

“Came straight here — guns drawn, pushed them to the ground, went up to the register, took the register,” said owner Mohammed Amed. “We had a firearm here, so they took the firearm and they just walked right out.”

This surveillance video from a bar next door shows the two men Amed said robbed his employees at gunpoint – walking out the door and taking off a little after 7:30 p.m. Wednesday, March 10.

“They were terrified,” Amed said. “One of them was a semiautomatic machine gun, one of them was a pistol, so they seemed like they knew what they were doing.”

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Despite a rise in robberies on the South Side recently, they’re down 9 percent citywide from this time last year.

Less than two weeks later, a similar robbery happened at the Dollar Tree at 54th Street and Western Avenue in the Gage Park neighborhood. A cashier was held at gunpoint and told to empty the register.

Now, police are warning businesses to be on the lookout.

“Don’t think it can’t happen to you,” Amed said. “All our customers who come in here are regulars and very friendly. We love everybody. And we still got hit.”

When it comes to the experience of the two masked men who held up his employees, Amed’s best guess is: “They’ve done it a thousand times. It wasn’t their first rodeo.”

That is why Chicago Police want your help catching the two suspects quickly, so it doesn’t happen again.

Merano did talk off camera to the clerk who was robbed at the Gage Park Dollar Tree. He said he’s just glad no one was hurt.

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If you have any information about either case, call Chicago Police Area One detectives at (312) 747-8382.

CBS 2 Chicago Staff